Plate heat exchanger

Abstract

A plate heat exchanger includes heat exchanger plates positioned between two end plates, a plurality of threaded tightening bolts each extending between one of the end plates and a drive unit, and through the other end plate, and a plurality of motors collectively defining the drive unit. The threaded tightening bolts each include a bolt head that bears directly/indirectly against the first or second end plate. A nut is in threaded engagement with each threaded tightening bolt and bears directly or indirectly against the second or first end plate so that the bolt head/nut associated with each threaded tightening bolt bear directly or indirectly against different ones of the first and second end plates. Each of the motors is operatively connected to a respective one of the threaded tightening bolts so that each of the threaded tightening bolts is rotatable independently of others of the threaded tightening bolts.

What is claimed is: 
     
       1. A plate heat exchanger comprising:
 a plurality of heat exchanger plates; 
 a first end plate; 
 a second end plate spaced apart from the first end plate, the plurality of heat exchanger plates being positioned between the first and second end plates; 
 a plurality of motors that collectively define a drive unit; 
 a plurality of threaded tightening bolts that each extend between the first end plate and the drive unit, each of the threaded tightening bolts also extending through the second end plate; 
 the threaded tightening bolts each including a respective bolt head that bears directly or indirectly against either the first end plate or the second end plate; 
 a plurality of nuts, each in threaded engagement with a respective one of the threaded tightening bolts and arranged to bear directly or indirectly against either the second end plate or the first end plate so that the bolt head and the nut associated with each respective threaded tightening bolt bear directly or indirectly against different ones of the first and second end plates; 
 the threaded tightening bolts and nuts being arranged for relative movement of the first and second end plates towards or away from each other; and 
 each of the plurality of motors being operatively connected to a respective one of the threaded tightening bolts so that each of the threaded tightening bolts is rotatable independently of others of the threaded tightening bolts, the bolt heads and the nuts being operatively coupled to the respective end plates in a manner such that operation of the respective motors and rotation of the threaded bolts in one direction decreases a distance between the end plates while operation of the respective motors and rotation of the threaded bolts in an opposite direction to the one direction increases the distance between the end plates. 
 
     
     
       2. The plate heat exchanger according to  claim 1 , wherein the plurality of threaded tightening bolts includes more than two threaded tightening bolts, and the plurality of motors includes more than two motors. 
     
     
       3. The plate heat exchanger according to  claim 1 , wherein the plurality of threaded tightening bolts includes more than three threaded tightening bolts, and the plurality of motors includes more than three motors. 
     
     
       4. The plate heat exchanger according to  claim 1 , in which at least one of the bolt heads is removably attached to the respective end plate against which the at least one bolt head directly or indirectly bears. 
     
     
       5. The plate heat exchanger according to  claim 1 , wherein each of the first and second end plates possesses a pair of oppositely positioned relatively longer sides and a pair of oppositely positioned relatively shorter sides, and each of the first and second end plates includes a recess on one of the relatively longer sides, at least one of the threaded tightening bolts being positioned in the recess. 
     
     
       6. The plate heat exchanger according to  claim 5 , wherein the at least one threaded tightening bolt positioned in the recess is a removable threaded tightening bolt that is removable from the recess. 
     
     
       7. A plate heat exchanger according to  claim 1 , wherein each of the plurality of motors is mounted in a housing. 
     
     
       8. The plate heat exchanger according to  claim 1 , wherein all of the plurality of motors are mounted in a common housing. 
     
     
       9. The plate heat exchanger according to  claim 1 , wherein the bolt heads and the nuts are fixed relative to the respective end plates to lock rotation of the bolt heads and the nuts relative to the respective end plates. 
     
     
       10. A plate heat exchanger comprising:
 two end plates spaced apart from one another; 
 a package of heat exchanger plates positioned between the two end plates; 
 a plurality of threaded tightening bolts that each extend from one of the end plates and through the other end plate; 
 the threaded tightening bolts each including a respective bolt head that is associated with and bears directly or indirectly against a first of the two end plates; 
 a plurality of nuts each in threaded engagement with a respective one of the threaded tightening bolts, each of the nuts being associated with and arranged to bear directly or indirectly against a second of the two end plates; 
 the threaded tightening bolts and the nuts being arranged to effect relative movement of the first end plate and the second end plate towards or away from each other; 
 a plurality of motors each operatively connected to a respective one of the threaded tightening bolts so that each motor rotates the respective threaded tightening bolt to rotate each of the threaded tightening bolts independently of others of the threaded tightening bolts, the bolt heads and the nuts being operatively coupled to the first and second end plates respectively in a manner such that operation of the respective motors and rotation of the threaded bolts in one direction decreases a distance between the end plates while operation of the respective motors and rotation of the threaded bolts in an opposite direction to the one direction increases the distance between the end plates; 
 the plurality of motors including a number of motors, the plurality of threaded bolts including a number of threaded tightening bolts; and 
 the number of threaded tightening bolts being equal to the number of motors. 
 
     
     
       11. The plate heat exchanger according to  claim 10 , wherein the plurality of motors includes more than two motors. 
     
     
       12. The plate heat exchanger according to  claim 10 , wherein the plurality of motors includes more than three motors. 
     
     
       13. The plate heat exchanger according to  claim 10 , in which at least one of the bolt heads is removably attached to the first end plate. 
     
     
       14. The plate heat exchanger according to  claim 10 , wherein each of the first and second end plates possesses a pair of oppositely positioned relatively longer sides and a pair of oppositely positioned relatively shorter sides, and each of the first and second end plates includes a recess on one of the relatively longer sides, at least one of the threaded tightening bolts being positioned in the recess. 
     
     
       15. The plate heat exchanger according to  claim 14 , wherein the at least one threaded tightening bolt positioned in the recess is a removable threaded tightening bolt. 
     
     
       16. A plate heat exchanger according to  claim 10 , wherein each of the plurality of motors is mounted in a housing. 
     
     
       17. The plate heat exchanger according to  claim 10 , wherein all of the motors are mounted in a common housing. 
     
     
       18. The plate heat exchanger according to  claim 10 , wherein the bolt heads and the nuts are fixed relative to the respective end plates to lock rotation of the bolt heads and the nuts relative to the respective end plates.